Rear steer setups and opinions

[jccarter1]

So currently in the process of building and Rockwell rig and I have tried to read up on what setups work the best, but there seems to be a little of lack of technical info about each setup and specs that people are acutally using not just what they heard works from some guy on the internet so if you have anything good to add please share.

My setup will be a ls motor with double ended Rams on both axles the rams are 2.5x10 if I recall correctly they are from surplus center and there has been plenty of people use these with very good results I intend to control the front with a orbital and rear with a electric joystick.

First thing i can't decide on is what size orbital to use I am leaning towards a 200cc I think that is around 9.6cu my current rig has a 160cc which is around 7.3cu and running a 2.5x8 psc ram it works good but at high speed you can get behind a little so how fast of a orbital can you go with the pressure that stock pumps produce and still have enough power to turn the tires if I had my way I would love a 1 turn lock to lock orbital but i don't know where that become a big trade off for power also if I do go with a faster orbital is there any options on pump upgrades that would help the pressure to help give it some more power

Pumps this is one were I have done lots of research and tried to learn as much as possible I have talk with a few people from different company's and most of the aftermarket pumps are really just stock pumps that have been rebuild with good OEM quality parts PSC used to offer two different styles of P pumps a 135 and a 185 now they just offer a 135 which is basically a stock pump I have seen people run one P pump for the whole system and run it thur the rear valve first then to the orbital the main downside I see with this is it will only do system at a time so it can be a little hit and miss on when you get steering. I have also considered
changing pumps and going to a twin pump setup which I am not 100% I could even fit inside the frame rails bc the only brackets I have seen put two pumps on the driverside and the alternator on top passenger so if I could find a bracket that just added a pump on the pass top that would be perfect

The last setup I have heard about but never seen in person is using a 12v hydraulic power unit those can be bought fairly cheap not real sure on speed and issues you might encounter by going that route if someone has info I would love to hear more about it

Well hopefully someone who is a little smarter can shed some light on some of these issues any help is appreciated

 

[Bebop]

Although I haven't build any 4WS system, I've done extensive research on them and talked to more than a few persons equipped with such systems. Patoyee's multiple posts and topic on the matter on PBB have been a huge help.

Pressure isn't what you're really going after in a 4WS application. Most stock pumps produce enough pressure to satisfyingly turn both front and rear no problem.

The downfall of a stock pump is volume. They don't move enough fluid to keep up with the demand of a fast steering input for both axles at the same time. What happens usually is the movement of either ram is too slow because it doesn't receive enough fluid to fill the ram quickly.

I'm a big fan of the twin pump system, as they effectively resolve the volume issue. Pressure stays the same, you just "doubled" your supply of fluid volume.

IMO two setups stand out, Goatbuilt's with dual pump on the driver side and alt on the pass side :

Patparts with everything on the driver side :

WideOpenDesign has something though to keep the stock accessory drive and add a pump on the pass side :

http://www.pirate4x4.com/forum/motor-tranny-t-case-performance/1020545-ls-engine-accessory-relocation-kit-2.html#post15052546

I like TC pumps are they're way smaller than a P-Pump, built to take a beating (needle bearings inside) and there is a readily available high flow version that you can get for next to nothing (Jeep WJ with hydraulic fan).

In order to decide on the orbital size, you need to calculate the volume of your ram. What's the shaft size of the SC rams you;re using ?

 

[Eddyj]

 

[NTIDWELL]

P pump running both ends sucks ass 200cc orbital dual tc pumps with 3"x9" rams sucks ass also. 200cc orbital dual tc pumps and 2.5 x 10 rams. My pumps was mounted like wide open designs. Stazworks rearsteer complete system is what I ran and love it Log splitter style works good also just takes up a lot more room than stazworks Plus side with log splitter style is engine doesn't have to be running to be able to steer

 

[Nuts]

2 pumps, 2 separate systems for best performance. I have driven rigs with high dollar single pump systems and they don't compare to medium/low dollar double pumps/double systems. Plus with 2 separate systems if 1 fails you can still steer with the other.